The present invention relates to a conveyor belt with a traction layer and with a polymer surface coating which comprises an antimicrobial additive, and also to a process for producing or repairing this conveyor belt.
Taking the example of conveyor belts used to transport foods, there is a risk that food constituents adhere to the surface of the belt and that microorganisms, e.g. microbes, bacteria, fungi, yeasts, viruses, etc., become established and may grow. These microorganisms impair the quality and durability of the transported food. They therefore have to be removed by frequent cleaning of the conveyor belts, and/or the possibility of their establishment and subsequent growth has to be prevented on the conveyor belts from the outset.
This has led, inter alia, to the development of conveyor belts provided throughout, or in individual layers, with antimicrobial additives. Antimicrobial additives here mean any of the active substances which kill microorganisms, e.g. microbes, bacteria, fungi, yeasts, viruses, etc., or inhibit their growth.
EP-B-0 818 405 discloses plastics conveyor belts which encompass a traction layer or encompass two traction layers bonded by an intermediate plastics layer, and to which a plastics layer has been laminated as conveying surface. This plastics layer comprises a composition with bis(2-pyridylthio-1-oxido)zinc as antimicrobial additive.
JP-A-4333406 discloses similarly structured food-conveyor belts in which the polymeric surface coating comprises imidazole-type additives to prevent mold.
These prior-art conveyor belts have the disadvantage that, for effective prevention of the establishment and growth of microorganisms on the conveying surface of the surface coating, relatively large amounts of antimicrobial additive have to be added in order to achieve a sufficiently high concentration, and this is firstly expensive and secondly can also have an adverse effect on the other properties of the conveyor belt.
In the light of the disadvantages of the previously known conveyor belts described above with antimicrobial additives, the invention is based on the following object: to provide a conveyor belt of the type mentioned at the outset which prevents establishment and growth of microorganisms on the conveying surface less expensively for the same effectiveness or more effectively for the same costs.
This object is achieved by the conveyor belt of the invention as defined in the appended claims.